Add Spark SQL connector (#277)

* Add SparkSQL connector

* Fix SparkSQL constructor

* Add query as mandatory field

* Add SparkSQLConnector test cases

* Move spark session init into test

Co-authored-by: huong.vuong <huong.vuong@grabtaxi.com>

src/main/java/io/github/setl/enums/Storage.java

@@ -14,6 +14,7 @@ public enum Storage {
     JDBC("io.github.setl.storage.connector.JDBCConnector"),
     STRUCTURED_STREAMING("io.github.setl.storage.connector.StructuredStreamingConnector"),
     HUDI("io.github.setl.storage.connector.HudiConnector"),
+    SPARK_SQL("io.github.setl.storage.connector.SparkSQLConnector"),
     OTHER(null);
 
     private String connectorName;

src/main/scala/io/github/setl/storage/connector/SparkSQLConnector.scala

@@ -0,0 +1,47 @@
+package io.github.setl.storage.connector
+
+import com.typesafe.config.Config
+import io.github.setl.config.Conf
+import io.github.setl.enums.Storage
+import io.github.setl.util.TypesafeConfigUtils
+import org.apache.spark.sql.DataFrame
+
+class SparkSQLConnector(val query: String) extends Connector {
+  override val storage: Storage = Storage.SPARK_SQL
+
+  def this(conf: Conf) = this(conf.get("query", ""))
+  def this(config: Config) = this(
+    query = TypesafeConfigUtils.getAs[String](config, "query").getOrElse("")
+  )
+
+  require(query.nonEmpty, "query is not defined")
+
+  /**
+   * Read data from the data source
+   *
+   * @return a [[DataFrame]]
+   */
+  @throws[org.apache.spark.sql.AnalysisException](s"$query is invalid")
+  override def read(): DataFrame = spark.sql(query)
+
+  /**
+   * Write a [[DataFrame]] into the data storage
+   *
+   * @param t      a [[DataFrame]] to be saved
+   * @param suffix for data connectors that support suffix (e.g. [[FileConnector]],
+   *               add the given suffix to the save path
+   */
+  override def write(t: DataFrame, suffix: Option[String]): Unit = {
+    if (suffix.isDefined) logWarning("suffix is not supported in SparkSQLConnector")
+    write(t)
+  }
+
+  /**
+   * Write a [[DataFrame]] into the data storage
+   *
+   * @param t a [[DataFrame]] to be saved
+   */
+  override def write(t: DataFrame): Unit = {
+    logWarning("write is not supported in SparkSQLConnector")
+  }
+}

src/test/resources/application.conf

@@ -263,3 +263,9 @@ hudi {
     hoodie.datasource.write.table.type = "MERGE_ON_READ"
   }
 }
+
+sparkSQL {
+  test {
+    query = "SELECT * FROM schema.table"
+  }
+}

src/test/scala/io/github/setl/config/Properties.scala

@@ -26,6 +26,7 @@ object Properties {
   val jdbcConfig: Config = cl.getConfig("psql.test")
 
   val hudiConfig : Config = cl.getConfig("hudi.test")
+  val sparkSQLConfig : Config = cl.getConfig("sparkSQL.test")
 
   val excelConfigConnector: Config = cl.getConfig("connector.excel")
   val cassandraConfigConnector: Config = cl.getConfig("connector.cassandra")

src/test/scala/io/github/setl/storage/connector/SparkSQLConnectorSuite.scala

@@ -0,0 +1,80 @@
+package io.github.setl.storage.connector
+
+import io.github.setl.config.{Conf, Properties}
+import io.github.setl.{SparkSessionBuilder, TestObject}
+import org.apache.spark.SparkConf
+import org.apache.spark.sql.SparkSession
+import org.scalatest.funsuite.AnyFunSuite
+
+class SparkSQLConnectorSuite extends AnyFunSuite{
+
+  val query : String =
+    """
+      | SELECT (ones.n1 + tens.n2 * 10) as user_id
+      | FROM (
+      |  SELECT 0 AS n1
+      |  UNION SELECT 1 AS n1
+      |  UNION SELECT 2 AS n1
+      |  UNION SELECT 3 AS n1
+      |  UNION SELECT 4 AS n1
+      |  UNION SELECT 5 AS n1
+      |  UNION SELECT 6 AS n1
+      |  UNION SELECT 7 AS n1
+      |  UNION SELECT 8 AS n1
+      |  UNION SELECT 9 AS n1
+      | ) ones
+      | CROSS JOIN
+      | (
+      |  SELECT 0 AS n2
+      |  UNION SELECT 1 AS n2
+      |  UNION SELECT 2 AS n2
+      |  UNION SELECT 3 AS n2
+      |  UNION SELECT 4 AS n2
+      |  UNION SELECT 5 AS n2
+      |  UNION SELECT 6 AS n2
+      |  UNION SELECT 7 AS n2
+      |  UNION SELECT 8 AS n2
+      |  UNION SELECT 9 AS n2
+      | ) tens
+      |""".stripMargin
+
+  val testTable: Seq[TestObject] = Seq(
+    TestObject(1, "p1", "c1", 1L),
+    TestObject(2, "p2", "c2", 2L),
+    TestObject(3, "p3", "c3", 3L)
+  )
+
+  val options : Map[String, String] = Map(
+    "query" -> query
+  )
+
+
+  test("Instantiation of constructors") {
+    val connector = new SparkSQLConnector(query)
+    assert(connector.query === query)
+
+    val testConfig = Properties.sparkSQLConfig
+    val connector2 = new SparkSQLConnector(testConfig)
+    assert(connector2.query === "SELECT * FROM schema.table")
+
+    val connector3 = new SparkSQLConnector(Conf.fromMap(options))
+    assert(connector3.query === query)
+
+    assertThrows[IllegalArgumentException](new SparkSQLConnector(""))
+    assertThrows[IllegalArgumentException](new SparkSQLConnector(Conf.fromMap(Map.empty)))
+    assertThrows[IllegalArgumentException](new SparkSQLConnector(testConfig.withoutPath("query")))
+  }
+
+  test("Read/Write of SparkSQLConnector") {
+    val spark: SparkSession = SparkSession.builder().config(new SparkConf()).master("local[*]").getOrCreate()
+    import spark.implicits._
+
+    val connector = new SparkSQLConnector(query)
+    assert(connector.read().collect().length == 100)
+
+    // Should log warning & do nothing
+    val testDF = testTable.toDF()
+    connector.write(testDF)
+    connector.write(testDF, Some("any_"))
+  }
+}